Air inlet control and method of operating a pump-turbine



Dec. 26, 1933. l.. F. MOODY I,941,361

AIR INLET CONTROL AND METHOD OF OPERATING A PUMP TURBINE Filed MaICh 14,1931 n- Illlll llllllllllllllllI Patented Dec. 1933 Perser @FFI-CE illuNl'lso STATES This invention relates to hydraulic machines andparticularly to an improved method of op- -eration of machines of thereversible pump-turbine type in changing from turbine to pump? operationand vice versa, andincludes improved air control mechanism for use incarrying outthis method as well as for use in hydraulic machines "suchas turbines or pumps in general. Y

In the operation of hydraulic turbines it is often desirable tounwate/rthe rotor to permit driving the machine with minimum friction losses.For instance, when a turbine-generator unit operates as a synchronouscondenser the tur'- bine gates are closed andthevacuum'in the draft tubebroken by admission of air thereto so as to unwater the runner, therebyallowing the runner-to rotatefreely in the air. The admission of thisair is effected usually automatically in accordance with the gateposition. In the case of reversible pump-turbines, or of ,pumps alone YLsometimesfit is desirable tocontrol air admission for the purpose ofpriming the pump or-'to insure 3 stability and smoothness of operation.The

automatic air control equipment heretofore used .od for changing fromturbine to. pump operayfor turbines alone doesY not havethat degree ofvflexibility of operation to renderrit efficienter entirely adapted forboth turbine andpump operations. y

Hence it is one object ofA my invention to provide an air controlmechanism'having an improved arrangement of elements so constructed andcoordinated in their functions thatthe desired ldegree and timing of aircontrol may be had for either turbine, pump or reversible pump-turbineunits. l Y A further object is to provide an improved arrangementwhereby-the Ausual automatic air control may be had for turbineoperation'but with an improved control adapted to supplement theautomatic control either by acting as anadjustment of the automaticcontrol or-of effecting air control independently of the position of theVautomatic control. Another and more specific object of the invention inthis respect'is to have the cooperating control subject to manualoperation p and preferablyV `operable independentlyV of the .automaticcontrol such, for instance, vas not being movable upon operation of theautomatic control and vice versa.

A still further specific object is to provide an improved air valvemechanism wherein the valve seat and cooperating valve member are eachmovable not only with respect to the valve casing but also with respectto each other.

fcompressed air.

A further object is to provide an improved air l admission control Afora reversible pump-turbine so'that the hand operation of the air valve`may beused in starting and synchronizing rthe vunit when operating as apump whereby the machine may be startedand-synchronized with the runnerrevolving in air and with the" guide vanes closed,

after which the air'inl'et may be closedv by hand and the runner spacebe allowed to ll with water. For low settings of the' runner, belowtailwater level,y compressedair maybe connected to the air 'valve andthe water forced vout of the runner space, with a second, hand operated,valve to relieve the air pressure after starting; or the compressed. airmay be admitted .through-a.` second valve-with Athev air vent-valveVas-shown herein used for relief after starting, thelatter being usuallythe preferable arrangement.

A further and more specific object of my invention Ais to provide avalve seat adjustably rotatable so that the gate position for closure oropening of the air valve may be deiinitely'adjusted by ahand wheel or ifdesired' adjusted by a motor operate through afremotecontrol. N v animproved meth- Another object is tol provide tion or vice versa.

Other objects and-advantagesnwill parent to those'skilled in the-artfrom the following description Vof the accompanying'drawing flFig. l isapartial plan view of'my improved yarranger'nent applied to a turbineofeither the Francis or 'high speciicspeed propeller: types its .operatingmechanism and lpart `of a Francis turbine; and I Fig. 3 is a partialplan view`of the valve and the operating gear.` y

Fig. 4 is a fragmentaryvertical section of'v a modified form of thevalve adapted for'fthe use of The invention as speciiicallyillustratedvherein lmay beapplied to diiferenttypes of turbines, suchasthe Francis or rhigh speciiic speed types, by'jhaving the adjustablegate mechanism operatively connected with my improved arrangementwhereby an air adnfiissionvr valve may be "controlled 'eitherautomatically in accordance be more .ap-

be clear from one specic form of the invention described herein wherewicket gates 1 are indicated in dotted lines and operated through usualgate arms 2 pivotally connected to connecting links 3 which in turn arepivotally connected to and actuated by a usual shifting ring 4. Thisring and the adjustable or wicket gates 1 are disposed, as is wellknown, concentrically to the axis of runner R.V Any suitable power meanssuch as a piston and cylinder motor, connected to a pivot 5 of theshifting ring, may be employed to oscillate the shifting ring to adjustthe wicket gates to their open or closed positions. It is seen thateither the movement or position of shifting ring 4 represents themovement or position of the wicket gates. Hence in the broader aspect ofthe invention the shifting ring, adjustable guide vanes and anyassociated linkages may be considered as gate or iiow control mechanism.The shifting ring and associated linkages are as shown in Fig. 2disposed above the usual turbine head cover 6.

To admit airwithin the runner passage P, preferably directly to thedraft tube as through suitable openings in the head cover or runner,

an inlet 7 provided with a ball-check valve is have an axial flange 13partially encircling the' seat 11 so as not only to increase theeffectiveness against leakage but also prevent dirt or other foreignmatter gaining access to the sliding surfaces. The seat has a series ofopenings 14 Aangularlyspaced so as to provide alternate closed portions15 of substantially similar extent to the openings. A portion of theperiphery of this seat is provided with a gear segment 11a which mesheswith a hand wheel operated pinion 11b, the hand wheel pinion beingcarried by basev 9. The gear ratio is preferably such as to cause uponone revolution of the hand wheel an angular displacement of seat 11substantially equal to the angular extent of the openings 14.

Also rotatably supported on stud 12 is a movable valve element 16 havingopenings l7'adapted to register with the openings `14. Openings 1'7likewise are angularly spaced so as to have closed portions therebetweenwhereby the openings 14 may be covered when desired.

An arm 18 normally xed to the hub of valve 16 by a set screw 18a butadapted to be freely rotatable thereon upon loosening of the set screw,

carries a roller 19 disposed within a slot 20 which is formed in a plate21, this in turn being secured preferably to the inside of the shiftingring 4 as by bolts 22. As seen in Fig. l the cam slot 20 has asubstantial arcuate portion concentric to the axis of the shifting ring4 and a small oirset portion 23. By loosening the set screw acompleteindependence is had between the two controls.

In turbine operation it is desired to open the air admission valve whenthe gate mechanism is in closed position. In this case the openings inboth the valve seat and movable valve element 16 are in register whichhas been effected due to roller 19 having engaged the surface of oisetcam slot 23, this cam surface having been moved into engagement with theroller when the shifting ring 4 was moved to closing position by thegate operating servo-motor. With the air valve thus open the draft tubewill be vented and the turbine allowed to rotate freely in air. When thegates open to a predetermined position, determined by the length of thearcuate slot 20, the air valve will close. The arcuate slot thusl delaysclosing of the air valve so that air is admitted to thedraft tube duringinitial part-gate operation oi the turbine, this being desirable.

1f the hydraulic machine is a reversible pumpturbine and itis desired tochange its operation from turbinel to pump, the machine will be broughtto a stop and the generator operated as a motor in the reversedirection, it being understood that the runner preferably has fixedblades or at least blades which are not adjustable past each other, thusnecessitating reverse direction of runner rotation for pump operation.With the machine now running in the reverse direction for pump operationand with the gates still closed and the vent open, the pump is primed byfirst closing the air control valve, this being possible in my improvedarrangement' notwithstanding that the gate mechanism is inclosedposition and the arm 18 is held against movement by roller 19 being inengagementwith the offset cam slot 23. The valve is closed merely byrotating the hand wheel operated pinion 11b, .thereby shifting the valveseat 11 relative to the other valve element 16 untilthe openings 17 ofthe latter are closed. Any suitable mechanism may now be employed toprime the pump either by an injector or other usuall arrangements. Afterthe pump is primed the gates are opened so kas to permit pump dischargetherethrough.` VI-f, during opening ofthe gates, the valve element 16 isactuated by the cam so astotend to open the air inlet then the handwheel-'control may again be superimposed on the action of the automaticcontrol so as to maintain the valve closed. If for any reason duringpump operation it should be desired in order to establish stability orsmoothness of operation, the air control valve may be opened to anydesired extent.

1t is thus seen that 1 have provided a very simple arrangement of partswhereby air control may be obtained for either pump or turbine operationby f' employing elements which are common to both operations, thusproviding a structure which is economical in initial cost ofconstruction and of maintenance in addition to having a wide range offlexibility as is necessary in a reversible pumpturbine machine. It isalso to be noted that in the specic valve shown one valve element actsas-a seat while the other is themovablevalve element and vice versa.

In some cases it may provide means for holding the air valve. closedindependently ofthe action of the gate operating mechanism and cam, touse the stationary disk 9a instead of just radial arms. The disk hasopenings registering with those in the movable seat 11 so that when theseat 11 is rotated by the handwheel so as to place the openings in 11above and in line with those -in9a, the openings will be controlledentirely by the operating mechanism and cam acting upon the valve disk17. rWhen the seat 11 is rotated so that its closed vportions cover theopenings in 9a, the valve remains closed independently of the motion ofthe valve disk 17 and of the turbine gates, Also, if seat 11 is adjustedto give a certain maximum opening then this can never be desirable, inorder to Y described.

be made larger by the movement of valve l'l a1- through it might be madesmaller thereby. If instead of using a disk 9a, radial Supporting armsare provided so as to have an opening over lthe Whole area then theoperation is as previously In the Fig. 4 modication' al suitable cover25 encloses the valve mechanism and operating gear, whereby compressedair may be supplied from any source through an inlet 26. In this figureis also shown a means of remote control by the use of an electricmotor-'27 geared tothe valve spindle, and having a sliding pinion r28for disengaging the motor drive to permit manual operation by thehandwheel Whendesired. It Will be understood that a similar remotecontrol device can'be applied to the other-forms of valve illustrated,

so that it is unnecessary to repeat this portion of Fig. 4 in the otherfigures as its applicationV to them will be obvious.

In the case of propeller turbines having adjustable runner blades' suchas is shown, 'for'examplf-z, in my copending application, Serial No.33,940, it is also possible, and may in some cases be desirable, to havethe air admission valve actuated or controlled oy the runnerblade'position rather than by the guide vane position. In describing theair valve as being controlled by the adjustable gate mechanism Itherefore intend to include itsl control by runner blade adjustmentsince such runner blade adjustment has the effect of con-` trolling theow and-may be considered to supplement or replace the control by theguide vane adjustment, being in the nature of a gate mechanism in whichthe runner blades perform the additional function of gates While inmotion with the remainder of the runner. vAdjustable runner blades maybe used as the sole flow control means n `It will of course beunderstood that various changesmay be Ymade in the construction, ar-Irangement and operationof parts and of the device as a whole, Withoutdeparting from' the spirit of my invention as set forth in the appendedclaims.

I claim: f y

1.`A hydraulic machine comprising, in combination, a runner, a passagetherefor, adjustable gate mechanism for .controlling the iloW throughsaid passage, an air inlet for said passage, means for controlling saidair inlet automatically in accordance with a predetermined gateposition, and means for additionally controlling the admission of air tosaid passage notwithstanding that the gate mechanism is in saidpredetermined position and having yprovision for determining the maximumextent of automatic air admission and of v limiting the same if desired.

2. A hydraulic machine comprising, in combination, a'runner, a passagetherefor, adjustable gate mechanism having actuating means, an in- `1etthrough which air is admitted to said runner passage, a valve mechanismfor said inlet, operating connections between said gate and inlet valvemechanism whereby the valve mechanism is adjusted automatically inaccordance withthe gate operation, and means for additionallycontrolling said air inlet while said operating connections remain innormal operative condition and having provision for limiting the maximumextent of automatic air admission. y

LEWIS YFERRY MOODY.

